This invention relates generally to tools for setting blind fasteners, such as blind rivets and the like. More particularly, this invention relates to an improved so-called pulling head for pulling and setting blind fasteners wherein the improved pulling head is quickly and easily adjustable to permit use with blind fasteners of different sizes and/or types.
Blind fasteners in general are relatively well known for connecting two or more lapped workpieces, particularly wherein the workpieces are accessible from one side only. Typically, such blind fasteners include a tubular sleeve having a diametric size to fit through aligned holes in the workpieces and an enlarged head at one end, in combination with a setting pin having an elongated pulling section sized to fit through the sleeve and a blind end expansion head sized to fit through the workpiece holes but not through the headed sleeve. In use, the blind fastener is assembled with the setting pin received through the sleeve with its pulling section projecting from the headed sleeve end and its expansion head abutting the opposite end of the sleeve. The thus-assembled fastener is then inserted through the aligned workpiece holes to position the sleeve head flush with the accessible side of the workpieces and the setting pin expansion head beyond the blind side of the workpieces. The blind fastener is set by pulling the setting pin toward the accessible side of the workpieces by means of an appropriate pulling tool, resulting initially in upsetting and enlargment of the blind sleeve end followed by progressive clamping of the workpieces tightly between the sleeve head and the now-enlarged blind sleeve end. Further application of pulling force to the setting pin severs or breaks the pin substantially flush with the sleeve head to provide a low profile fastener clamping the workpieces tightly together. Exemplary blind fasteners of this general type are shown and described in U.S. Pat. No. 4,407,619.
A variety of setting tools have been proposed for use in pulling and setting blind fasteners of the above-referenced type. These setting tools, commonly referred to as "pulling heads," have generally included a so-called draw bolt assembly mounted for sliding movement within a tool housing, wherein the draw bolt assembly and tool housing are adapted for removable mounting onto an appropriate power-driven or manually operated pulling mechanism. The draw bolt assembly includes means for grasping and pulling a blind fastener setting pin guidably inserted into the tool housing through a housing nose cap. Examples of such pulling heads are those marketed by Olympic Fastening Systems of Downey, Calif., under the model designations RV811 and RV812.
However, in such previous pulling heads, the nose cap for the tool housing has generally been designed for use with a fastener setting pin of a single size. Alternatively, in some instances, the housing nose cap has included an exterior surface geometry for use with a blind fastener of a single type. Accordingly, it has been necessary to acquire several different pulling heads of different sizes and/or types to provide the desirable capability to install blind fasteners of different sizes or types. This requirement for multiple pulling heads, however, undesirably increases user costs and further requires time-consuming interchanging of pulling heads on a pulling mechanism whenever a blind fastener of a different size or type is desired. Moreover, unused pulling heads are subject to occasional misplacement to further increase user inconvenience and/or cost.
There exists, therefore, a significant need for an improved pulling head for setting blind fasteners wherein the pulling head is adjustable quickly and easily without removal of components therefrom to accommodate blind fasteners of different sizes and/or types. The present invention fulfills this need and provides further related advantages.